The present invention relates to O/W (oil-in-water) nanoemulsions comprising oil globules with an average size of less than 150 nm comprising at least one oil, at least one amphiphilic lipid, and at least one PEG (poly ethylene glycol) derivative chosen from specific PEG esters and PEG ethers. The present invention also relates to the use of such nanoemulsions in topical application, for example, in cosmetics and/or in dermopharmacy.
The term xe2x80x9cnanoemulsionxe2x80x9d means a metastable oil-in-water emulsion (wherein, for example, the emulsion can comprise an oily phase dispersed in an aqueous phase) whose oil globule size is less than 150 nm, these oil globules being stabilized with a crown of amphiphilic lipids which can optionally form a liquid crystal phase of lamellar type located at the oil/aqueous phase interface. The transparency of these emulsions derives from the small size of the oil globules, wherein said small size can be obtained for example by using a high-pressure homogenizer. Nanoemulsions are to be distinguished from microemulsions by their structure. Microemulsions are thermodynamically stable dispersions comprising micelles of at least one amphiphilic lipid swollen with oil. Furthermore, microemulsions do not require considerable mechanical energy to be prepared. They form spontaneously simply by placing the constituents in contact. At least one possible drawback of microemulsions can be associated with the presence of a high proportion of surfactants, which may tend to lead to intolerance and entailing a sticky feel when applied to the skin. Moreover, their field of formulation is generally narrow and their temperature stability can be limited.
The at least one (as used throughout herein above and below, the expression xe2x80x9cat least onexe2x80x9d means one or more and thus includes individual components as well as mixtures/combinations) amphiphilic lipid is present in an amphiphilic lipid phase, which comprises at least one amphiphilic lipid chosen from for example nonionic and ionic amphiphilic lipids. The expression xe2x80x9camphiphilic lipidxe2x80x9d means any molecule of bipolar structure comprising at least one hydrophobic portion and at least one hydrophilic portion having the property of reducing the surface tension of water (g less than 55 mN/m) and of reducing the interface tension between water and an oily phase. The synonyms of amphiphilic lipid are, for example: surfactant, surface agent, and emulsifier.
The prior art discloses nanoemulsions comprising an amphiphilic lipid phase comprising phospholipids, a cationic lipid, water and al hydrophobic sunscreen. They are obtained by a high-pressure homogenization process. These nanoemulsions can have at least one drawback, for example, such nanoemulsion s may tend to be unstable on storage at the conventional storage temperatures, i.e., between 0xc2x0 C. and 45xc2x0 C. Such nanoemulsions may lead to yellow compositions and may produce unpleasant odors, which may develop after a few days of storage. Furthermore, such nanoemulsions tend to exhibit less favorable cosmetic properties. They are described in the xe2x80x9cDCIxe2x80x9d review of April 1996, pages 46-48, the disclosure of which is incorporated by reference herein.
Moreover, documents EP-A-728 460 and EP-A-780 114, the disclosures of which are incorporated by reference herein, disclose nanoemulsions based on fluid nonionic amphiphilic lipids and on silicone surfactants.
However, all these nanoemulsions are fluid. For certain uses, products are sought which can be measured out and taken up easily by hand. To do this, these products must have a certain level of consistency or viscosity. Specifically, a liquid product may be more difficult to measure out and tends to run easily between the fingers.
It is known practice to use, as thickeners for aqueous media, water-soluble or water-dispersible polymers, such as optionally crosslinked polymers for example polycarboxyvinylic acids, such as carbopol, wherein said polymers can have a long chain length and a high molecular weight.
When such polymers are used in compositions in the form of nanoemulsions, some of such nanoemulsions may tend to exhibit a decrease in at least one characteristic, such as stability and transparency.
Thus, there is still a need for a thickening system which can conveniently thicken, or even gel, a composition in the form of an oil-in-water nanoemulsion, while minimizing any possible influence that it may have on the cosmetic properties of said compositions.
The inventors have discovered, unexpectedly, that oil-in-water nanoemulsions comprising oil globules with an average size of less than 50 nm comprising at least one oil, and at least one amphiphilc lipid can be thickened with at least one PEG (poly ethylene glycol) derivative chosen from specific PEG esters and PEG ethers.
One subject of the present invention is oil-in-water nanoemulsions comprising oil globules with an average size of less than 150 nm comprising at least one oil, at least one amphiphilc lipid, and at least one PEG (poly ethylene glycol) derivative chosen from specific PEG esters and PEG ethers defined below, wherein the weight ratio of the amount of said at least one oil to the amount of said at least one amphiphilic lipid ranges for example from 1:1 to 10:1, such as for example from 1.2:1 to 6:1.
Another subject of the invention is a process for thickening oil-in-water nanoemulsions comprising oil globules with an average size of less than 150 nm comprising at least one oil and at least one amphiphilc lipid comprising including at least one PEG (poly ethylene glycol) derivative chosen from specific PEG esters and PEG ethers defined below in said nanoemulsions.
As a non-restrictive explanation, it may be considered that, in the context of the invention, the increase in the viscosity of the medium may result from the formation of a network of oil particles, said network involving combinations of hydrophobic type between, on the one hand, the hydrophobic groups of the polymer and, on the other hand, the hydrophobic cores of the oil particles. The existence of labile bonds between the particles may be responsible in part for increasing the viscosity of the mixture.
The nanoemulsions in accordance with the invention are prepared at temperatures ranging for example from 4xc2x0 C. to 45xc2x0 C. and are compatible with heat-sensitive active agents. If desired, the nanoemulsions can comprise large amounts of oil. Such nanoemulsions can for example comprise large amounts of fragrance and can improve their remanence. They can also promote the penetration of the active agents into the superficial layers of the skin and the deposition of active agent onto keratin fibres such as the hair. Hair treated with these nanoemulsions may be at least one of the following: shiny, while simultaneously avoiding a greasy look or feel, softer and more lively in nature, while also tending to disentangle easily.
The cosmetic composition, such as for example a hair composition, obtained by comprising the nanoemulsions of the present invention may spread easily, may be easier to handle and may be removed satisfactorily by rinsing.
The at least one PEG (poly ethylene glycol) derivative chosen from PEG esters and PEG ethers can be, for example, chosen from compounds of formula (I):
R1xe2x80x94(Oxe2x80x94CH2xe2x80x94CH2)nxe2x80x94OR2xe2x80x83xe2x80x83(I)
in which:
R1 is chosen from linear and branched, saturated and unsaturated alkyl groups comprising from 8 to 30 carbon atoms and linear and branched, saturated and unsaturated acyl groups comprising from 8 to 30 carbon atoms,
R2 is chosen from a hydrogen atom, linear and branched, saturated and unsaturated alkyl groups comprising from 1 to 30 carbon atoms, and linear and branched, saturated and unsaturated acyl groups comprising from 1 to 30 carbon atoms, and
n is a number ranging from 80 to 350.
In one embodiment, R1 can be for example chosen from acyl groups comprising from 12 to 20 carbon atoms. In another embodiment, R2 can be for example chosen from acyl groups comprising from 12 to 20 carbon atoms. In yet another embodiment, n can be for example a number ranging from 100 to 300. The weight ratio between the hydrophilic portion (xe2x80x94(Oxe2x80x94CH2xe2x80x94CH2)nOxe2x80x94) and the hydrophobic portion (chosen from R1, R2, and R1 and R2) ranges for example from 8:1 to 1000:1.
In one embodiment, a compound of formula (I) that can be used is one in which R1 and R2 are acyl groups comprising from 12 to 20 carbon atoms and n ranges from 100 to 300. Mention may be made, for example, of PEG 150 distearate and PEG 250 distearate.
Such compounds for example are sold under the name Emanon 3299R by the company KAO and under the name Kessco PEG 6000 DS by the company Akzo.
In the compositions according to the invention, the at least one PEG derivative chosen from PEG esters and PEG ethers of formula (I) is generally present in an amount ranging for example from 0.01% to 20% by weight relative to the total weight of the composition, such as for example from 0.1% to 10% by weight relative to the total weight of the composition.
The nanoemulsions according to the present invention can comprise at least one amphiphilic lipid chosen from for example nonionic amphiphilic lipids and anionic amphiphilic lipids.
The nonionic amphiphilic lipids of the invention can be chosen from, for example:
1/xe2x80x94silicone surfactants,
2/xe2x80x94nonionic amphiphilic lipids that are fluid at a temperature of less than or equal to 45xc2x0 C. chosen from esters formed from (i) at least one polyol chosen from polyethylene glycol comprising from 1 to 60 ethylene oxide units, sorbitan, glycerol comprising from 2 to 30 ethylene oxide units, polyglycerols comprising from 2 to 15 glycerol units, and (ii) at least one fatty acid comprising at least one alkyl chain chosen from saturated and unsaturated, linear and branched C8-C22 alkyl chains,
3/xe2x80x94mixed esters derived from (i) at least one fatty acid, at least one carboxylic acid, and glycerol, and mixed esters derived from (ii) at least one fatty alcohol, at least one carboxylic acid, and glycerol, wherein said at least one carboxylic acid is chosen from xcex1-hydroxy acids and succinic acid,
4/xe2x80x94fatty acid esters of sugars and fatty alcohol ethers of sugars,
5/xe2x80x94surfactants that are solid at a temperature of less than or equal to 45xc2x0 C. chosen from fatty esters of glycerol, fatty esters of sorbitan, oxyethylenated fatty esters of sorbitan, ethoxylated fatty ethers, and ethoxylated fatty esters, and
6/xe2x80x94block copolymers of ethylene oxide (A) and of propylene oxide (B).
1/ The silicone surfactants that can be used according to the invention are silicone compounds comprising at least one oxyalkylene chain chosen from oxyethylene xe2x80x94OCH2CH2xe2x80x94 and oxypropylene xe2x80x94OCH2CH2CH2xe2x80x94. Representative silicone surfactants that can be used according to the present invention include silicone surfactants disclosed in U.S. Pat. Nos. 5,364,633 and 5,411,744, the disclosures of which are incorporated by reference herein.
The silicone surfactants used according to the present invention can be chosen for example from compounds of formula (I): 
in which:
R1, R2 and R3, which may be identical or different, are each chosen from C1-C6 alkyl groups and groups of the formula xe2x80x94(CH2)xxe2x80x94(OCH2CH2)yxe2x80x94(OCH2CH2CH2)zxe2x80x94OR4, provided that at least one of said groups R1, R2 and R3 is not a C1-C6 alkyl group;
R4 is chosen from hydrogen, alkyl groups, and acyl groups;
A is chosen from integers ranging from 0 to 200;
B is chosen from integers ranging from 0 to 50; with the proviso that A and B are not simultaneously equal to zero;
x is chosen from integers ranging from 1 to 6;
y is chosen from integers ranging from 1 to 30;
z is chosen from integers ranging from 0 to 5.
In one embodiment of the invention, in the compound of formula (I) said alkyl groups are methyl groups, x is chosen from integers ranging from 2 to 6 and y is chosen from integers ranging from 4 to 30.
Representative examples of silicone surfactants of formula (I) can include the compounds of formula (II): 
in which A is chosen from integers ranging from 20 to 105, B is chosen from integers ranging from 2 to 10 and y is chosen from integers ranging from 10 to 20.
Representative examples of silicone surfactants of formula (I) can include the compounds of formula (III):
Hxe2x80x94(OCH2CH2)yxe2x80x94(CH2)3xe2x80x94[(CH3)2SiO]Axe2x80x2xe2x80x94(CH2)3xe2x80x94(OCH2CH2)yxe2x80x94OHxe2x80x83xe2x80x83(III)
in which Axe2x80x2 and y, which may be identical or different, are each chosen from integers ranging from 10 to 20.
Silicone surfactants of the invention which may be used for example are the silicone surfactants sold by the company Dow Corning under the names DC 5329, DC 7439-146, DC 2-5695, and Q4-3667. The products DC 5329, DC 7439-146, and DC 2-5695 are silicone surfactants of formula (II) in which, respectively, A is 22, B is 2, and y is 12; A is 103, B is 10, and y is 12; A is 27, B is 3, and y is 12.
The product Q4-3667 is a compound of formula (III) in which A is 15 and y is 13.
2/ The amphiphilic lipids that are fluid at a temperature of less than or equal to 45xc2x0 C. are chosen from, for example:
the isostearate of polyethylene glycol of molecular weight 400, sold under the name PEG 400 by the company Unichema;
diglyceryl isostearate, sold by the company Solvay;
glyceryl laurate comprising 2 glycerol units, sold by the company Solvay;
sorbitan oleate, sold under the name SPAN 80 by the company ICI;
sorbitan isostearate, sold under the name NIKKOL SI 10R by the company Nikko;
xcex1-butylglucoside cocoate and xcex1-butylglucoside caprate, sold by the company Ulice.
3/ The mixed esters derived from (i) at least one fatty acid, at least one carboxylic acid, and glycerol, and the mixed esters derived from (ii) at least one fatty alcohol, at least one carboxylic acid, and glycerol, wherein said at least one carboxylic acid is chosen from xcex1-hydroxy acids and succinic acid, which can be used as surfactants in the nanoemulsion according to the invention, may be chosen from, for example, (a) mixed esters derived from at least one fatty acid comprising at least one alkyl chain comprising from 8 to 22 carbon atoms, at least one xcex1-hydroxy acid, and glycerol, (b) mixed esters derived from at least one fatty acid comprising at least one alkyl chain comprising from 8 to 22 carbon atoms, succinic acid, and glycerol, (c) mixed esters derived from at least one fatty alcohol comprising at least one alkyl chain comprising from 8 to 22 carbon atoms, at least one xcex1-hydroxy acid, and glycerol, and (d) mixed esters derived from at least one fatty alcohol comprising at least one alkyl chain comprising from 8 to 22 carbon atoms, succinic acid, and glycerol. The xcex1-hydroxy acid may be chosen, for example, from at least one acid chosen from citric acid, lactic acid, glycolic acid and malic acid.
The alkyl chain of the fatty acids and fatty alcohols from which are derived the mixed esters which can be used in the nanoemulsion of the invention may be chosen from linear and branched, saturated and unsaturated alkyl chains. For example, the alkyl chain may be at least one chain chosen from stearate, isostearate, linoleate, oleate, behenate, arachidonate, palmitate, myristate, laurate, caprate, isostearyl, stearyl, linoleyl, oleyl, behenyl, myristyl, lauryl and capryl chains.
As examples of mixed esters which can be used in the nanoemulsion of the invention, mention may be made of the mixed ester of glycerol and of the mixture of citric acid, lactic acid, linoleic acid and oleic acid (CTFA name: Glyceryl citrate/lactate/linoleate/oleate) sold by the company Hxc3xcls under the name Imwitor 375; the mixed ester of succinic acid and of isostearyl alcohol with glycerol (CTFA name: Isostearyl diglyceryl succinate) sold by the company Hxc3xcls under the name Imwitor 780 K; the mixed ester of citric acid and of stearic acid with glycerol (CTFA name: Glyceryl stearate citrate) sold by the company Hxc3xcls under the name Imwitor 370; the mixed ester of lactic acid and of stearic acid with glycerol (CTFA name: Glyceryl stearate lactate) sold by the company Danisco under the name Lactodan B30 or Rylo LA30.
4/ Fatty acid esters of sugars, which can be used as surfactants in the nanoemulsion according to the invention, can be chosen from fatty acid esters of sugars that are solid at a temperature of less than or equal to 45xc2x0 C., such as esters derived from at least one C8-C22 fatty acid and at least one sugar chosen from sucrose, maltose, glucose, and fructose, and esters derived from at least one C14-C22 fatty acid and methylglucose.
The C8-C22 and C14-C22 fatty acids forming the fatty unit of the esters which can be used in the nanoemulsion of the invention comprise an alkyl chain chosen from saturated and unsaturated linear alkyl chains comprising, respectively, from 8 to 22 and from 14 to 22 carbon atoms. The fatty unit of the esters may be formed for example from stearates, behenates, arachidonates, palmitates, myristates, laurates and caprates. In one embodiment of the invention, stearates for example may be used as the fatty unit.
As examples of esters of at least one fatty acid and of sucrose, of fatty acids and of maltose, of fatty acids and of glucose, and of fatty acids and of fructose, mention may be made of sucrose monostearate, sucrose distearate and sucrose tristearate and mixtures thereof, such as the products sold by the company Croda under the name Crodesta F50, F70, F110 and F160 having, respectively, an HLB (hydrophilic lipophilic balance) of 5, 7, 11 and 16; and examples of esters of at least one fatty acids and of methylglucose which may be mentioned are methylglucose polyglyceryl-3 distearate, sold by the company Goldschmidt under the name Tego-care 450. Mention may also be made of glucose or maltose monoesters such as methyl o-hexadecanoyl-6-D-glucoside and o-hexadecanoyl-6-D-maltoside.
The fatty alcohol ethers of sugars, which can be used as surfactants in the nanoemulsion according to the invention, are solid at a temperature of less than or equal to 45xc2x0 C. and may be chosen for example from ethers of at least one C8-C22 fatty alcohol and of glucose, of at least one C8-C22 fatty alcohol and of maltose, of at least one C8-C22 fatty alcohol and of sucrose, and of at least one C8-C22 fatty alcohol and of fructose, and ethers of at least one C14-C22 fatty alcohol and of methylglucose. An example of such an ether would include, among other ethers, alkylpolyglucosides.
The at least one C8-C22 and the at least one C14-C22 fatty alcohols forming the fatty unit of the ethers which may be used in the nanoemulsion of the invention can comprise at least one alkyl chain chosen from saturated and unsaturated, linear alkyl chains comprising, respectively, from 8 to 22 and from 14 to 22 carbon atoms. The fatty unit of the ethers may be chosen for example from decyl, cetyl, behenyl, arachidyl, stearyl, palmityl, myristyl, lauryl, capryl and hexadecanoyl units, and further such as cetearyl.
As examples of fatty alcohol ethers of sugars, mention may be made of alkylpolyglucosides such as decylglucoside and laurylglucoside, which is sold, for example, by the company Henkel under the respective names Plantaren 2000 and Plantaren 1200, cetostearyl glucoside optionally as a mixture with cetostearyl alcohol, sold for example, under the name Montanov 68 by the company SEPPIC, under the name Tego-care CG90 by the company Goldschmidt and under the name Emulgade KE3302 by the company Henkel, as well as arachidyl glucoside, for example in the form of a mixture of arachidyl alcohol and behenyl alcohol and arachidyl glucoside, sold under the name Montanov 202 by the company SEPPIC.
In one embodiment of the invention, the surfactant used can be for example at least one surfactant chosen from sucrose monostearate, sucrose distearate and sucrose tristearate. Additional surfactants that can be used include methylglucose polyglyceryl-3 distearate and alkylpolyglucosides.
5/ The fatty esters of glycerol which may be used as surfactants in the nanoemulsion according to the invention, which are solid at a temperature of less than or equal to 45xc2x0 C., may be chosen for example from esters formed from at least one acid comprising a saturated linear alkyl chain comprising from 16 to 22 carbon atoms and from 1 to 10 glycerol units. One or more of these fatty esters of glycerol may be used in the nanoemulsion of the invention.
These esters may be chosen for example from stearates, behenates, arachidates and palmitates. In one embodiment, the esters may be chosen for example from stearates and palmitates.
As examples of surfactants which can be used in the nanoemulsion of the invention, mention may be made of decaglyceryl monostearate, distearate, tristearate and pentastearate (CTFA names: Polyglyceryl-10 stearate, Polyglyceryl-10 distearate, Polyglyceryl-10 tristearate, Polyglyceryl-10 pentastearate), such as the products sold under the respective names Nikkol Decaglyn 1-S, 2-S, 3-S and 5-S by the company Nikko, and diglyceryl monostearate (CTFA name: Polyglyceryl-2 stearate), such as the product sold by the company Nikko under the name Nikkol DGMS.
The fatty esters of sorbitan which may be used as surfactants in the nanoemulsion according to the invention are solid at a temperature of less than or equal to 45xc2x0 C. and are chosen from C16-C22 fatty acid esters of sorbitan and oxyethylenated C16-C22 fatty acid esters of sorbitan. They are formed from (i) at least one fatty acid comprising at least one saturated linear alkyl chain comprising, respectively, from 16 to 22 carbon atoms, and from sorbitol, as well as from (ii) at least one fatty acid comprising at least one saturated linear alkyl chain comprising, respectively, from 16 to 22 carbon atoms, and from ethoxylated sorbitol. The oxyethylenated esters generally comprise from 1 to 100 ethylene glycol units, such as from 2 to 40 ethylene oxide (EO) units.
These esters may be chosen for example from stearates, behenates, and arachidates, palmitates. In one embodiment, the esters may be chosen for example from stearates and palmitates.
As examples of surfactants which can be used in the nanoemulsion of the invention, mention may be made of sorbitan monostearate (CTFA name: sorbitan stearate), sold by the company ICI under the name Span 60, sorbitan monopalmitate (CTFA name: sorbitan palmitate), sold by the company ICI under the name Sipan 40, and sorbitan tristearate 20 EO (CTFA name: Polysorbate 65), sold by the company ICI under the name Tween 65.
The ethoxylated fatty ethers that are solid at a temperature of less than or equal to 45xc2x0 C., which may be used as surfactants in the nanoemulsion according to the invention, can be ethers formed from 1 to 60 ethylene oxide units and from at least one fatty alcohol chain comprising from 16 to 22 carbon atoms. The at least one fatty chain of the ethers may be chosen for example from behenyl, arachidyl, stearyl and cetyl units, and further for example from cetearyl. Examples of ethoxylated fatty ethers which may be mentioned are behenyl alcohol ethers comprising 5, 10, 20 and 30 ethylene oxide units (CTFA names: Beheneth-5, Beheneth-10, Beheneth-20, Beheneth-3C)), such as the products sold under the names Nikkol BB5, BB10, BB20 and BB30 by the company Nikko, and stearyl alcohol ether comprising 2 ethylene oxide units (CTFA name: steareth-2), such as the product sold under the name Brij 72 by the company ICI.
The ethoxylated fatty esters that are solid at a temperature of less than or equal to 45xc2x0 C., which may be used as surfactants in the nanoemulsion according to the invention, are esters formed from 1 to 60 ethylene oxide units and from at least one fatty acid chain comprising from 16 to 22 carbon atoms. The at least one fatty chain in the esters may be chosen for example from stearate, behenate, arachidate and palmitate units. Examples of ethoxylated fatty esters which may be mentioned are the ester of stearic acid comprising 40 ethylene oxide units, such as the product sold under the name Myrj 52 (CTFA name: PEG40 stearate) by the company ICI, as well as the ester of behenic acid comprising 8 ethylene oxide units (CTFA name: PEG-8 behenate), such as the product sold under the name Compritol HD5 ATO by the company Gattefosse.
6/ The block copolymers of ethylene oxide (A) and of propylene oxide (B), which may be used as a surfactant in the nanoemulsion according to the invention, may be chosen for example from at least one block copolymer of formula (I):
HO(C2H4O)x(C3H6O)y(C2H4O)zHxe2x80x83xe2x80x83(I)
in which x, y, and z, which may be identical or different, are each chosen from integers wherein x+z is an integer ranging from 2 to 100 and y is an integer ranging from 14 to 60, and optionally having an HLB value ranging from 2 to 16.
The at least one block copolymer of formula (I) may be chosen for example from poloxamers, such as Poloxamer 231, and further such as the product sold by the company ICI under the name PLURONIC L81, which corresponds to the block copolymer of formula (I) wherein x=z=6, y=39 (HLB 2); Poloxamer 282, such as the product sold by the company ICI under the name PLURONIC L92, which corresponds to the block copolymer of formula (I) wherein x=z=10, y=47 (HLB 6); and Poloxamer 124, such as the product sold by the company ICI under the name PLURONIC L44, which corresponds to the block copolymer of formula (I) wherein x=z=11, y=21 (HLB 16).
Representative nonionic amphiphilic lipids that can be used for example are chosen from:
polyethylene glycol isostearate (8 mol of ethylene oxide),
diglyceryl isostearate,
polyglyceryl monolaurate, polyglyceryl monostearate, and polyglyceryl distearate, which comprise 10 glycerol units,
sorbitan oleate, and
sorbitan isostearate.
Representative anionic amphiphilic lipids of the invention, for example, can be chosen from:
alkyl ether citrates,
alkoxylated alkenyl succinates,
alkoxylated glucose alkenyl succinates, and
alkoxylated methylglucose alkenyl succinates.
The alkyl ether citrates which may be used as surfactants in the nanoemulsion according to the invention may be chosen for example from at least one alkyl ether citrate chosen from monoesters, diesters, and triesters formed from citric acid and from at least one oxyethylenated fatty alcohol comprising at least one alkyl chain chosen from linear and branched, saturated and unsaturated alkyl chains comprising from 8 to 22 carbon atoms, and comprising from 3 to 9 ethoxylated groups. One embodiment of the invention may comprise at least one of the above-mentioned citrates in the nanoemulsion. Another embodiment may comprise at least two of the above-mentioned citrates in the nanoemulsion.
These citrates may be chosen, for example, from the monoesters, diesters, and triesters of citric acid and of ethoxylated lauryl alcohol, comprising from 3 to 9 ethoxylated groups, which are, for example, sold by the company Witco under the name WITCONOL EC. For example, WITCONOL EC 2129, which is predominantly a dilaureth-9 citrate, and Witconol EC 3129, which is predominantly a trilaureth-9 citrate, can be chosen.
When used, the alkyl ether citrates used as surfactants can for example be neutralized to a pH of about 7 with at least one base chosen from inorganic bases (such as sodium hydroxide, potassium hydroxide and ammonia) and organic bases (such as monoethanolamine, diethanolamine, triethanolamine, 1,3-aminomethylpropanediol, N-methylglucamine and basic amino acids like arginine and lysine).
The alkenyl succinates which may be used as surfactants in the nanoemulsion of the invention can, for example, be chosen from alkoxylated alkenyl succinates, alkoxylated glucose alkenyl succinates, and alkoxylated methylglucose alkenyl succinates that correspond to compounds of formulae (I) and (II):
HOOCxe2x80x94CHRxe2x80x94CH2xe2x80x94COOxe2x80x94Exe2x80x83xe2x80x83(I)
HOOCxe2x80x94CHRxe2x80x94CH2xe2x80x94COOxe2x80x94Exe2x80x94Oxe2x80x94COxe2x80x94CH2xe2x80x94CHRxe2x80x2xe2x80x94COOHxe2x80x83xe2x80x83(II)
in which:
R and Rxe2x80x2, which may be identical or different, are each chosen from linear and branched alkenyl groups comprising from 6 to 22 carbon atoms,
E is chosen from oxyethylene chains of formula (C2H4O)n in which n is chosen from integers ranging from 2 to 100, oxypropylene chains of formula (C3H6O)nxe2x80x2 in which nxe2x80x2 is chosen from integers ranging from 2 to 100, and random and block copolymers comprising chains chosen from oxyethylene chains of formula (C2H4O)n and oxypropylene chains of formula (C3H6O)nxe2x80x2 (such as oxyethylenated glucose copolymers, oxyethylenated methylglucose copolymers, oxypropylenated glucose copolymers, and oxypropylenated methylglucose copolymers) such that:
the sum of n and nxe2x80x2 is an integer ranging from 2 to 100,
the oxyethylenated and oxypropylenated glucose groups of said oxyethylenated and oxypropylenated glucose copolymers comprise on average from 4 to 100, respectively, oxyethylene or oxypropylene units distributed on all the hydroxyl functions, and
the oxyethylenated and oxypropylenated methylglucose groups of said oxyethylenated and oxypropylenated methyl glucose copolymers comprise on average from 4 to 100 oxyethylene or oxypropylene units distributed on all the hydroxyl functions.
In formulae (I) and (II), n and nxe2x80x2 are average values and are thus not necessarily integers. In one embodiment of the invention, n is chosen from integers ranging from 5 to 60, such as from 10 to 30.
In one embodiment, R and Rxe2x80x2, which may be identical or different, are each chosen from linear alkenyl groups comprising from 8 to 22 carbon atoms, such as from 14 to 22 carbon atoms. R and Rxe2x80x2, which may be identical or different, each may be, for example, chosen from the hexadecenyl group comprising 16 carbon atoms and the octadecenyl group comprising 18 carbon atoms.
The compounds of formulae (I) and (II) described above, in which E is chosen from oxyethylene chains, oxypropylene chains and copolymers comprising oxyethylene chains and oxypropylene chains, may be prepared in accordance with the description given in documents WO-A-94/00508, EP-A-107 199 and GB-A-2 131 820, which are incorporated herein by reference.
The acid function xe2x80x94COOH in the surfactants of formulae (I) and (II) is generally in the nanoemulsion of the invention in a form which is neutralized with a neutralizing agent chosen, for example, from inorganic bases (such as sodium hydroxide, potassium hydroxide and ammonia) and organic bases (such as monoethanolamine, diethanolamine, triethanolamine, 1,3-aminomethylpropanediol, N-methylglucamine, and basic amino acids, such as arginine and lysine).
Representative surfactants which can be used in the nanoemulsion of the invention, include at least one surfactant chosen from hexadecenyl succinate 18 EO (compound of formula (I) with R=hexadecenyl, E=(C2H4O)n, n=18), hexadecenyl succinate 45 EO (compound of formula (I) with R=hexadecenyl, E=(C2F4O)n, n=45), dihexadecenyl succinate 18 EO (compound of formula (II) with R=Rxe2x80x2=hexadecenyl, E=(C2H4O)n, n=18), dihexadecenyl glucose succinate 10 EO (compound of formula (II) with R=Rxe2x80x2=hexadecenyl, E=oxyethylenated glucose containing 10 oxyethylene groups), dihexadecenyl glucose succinate 20 EO (compound of formula (II) with R=Rxe2x80x2-hexadecenyl, E=oxyethylenated glucose containing 20 oxyethylene groups), and dioctadecenyl methylglucose succinate 20 EO (compound of formula (II) with R=Rxe2x80x2=octadecenyl, E=oxyethylenated methylglucose containing 20 oxyethylene groups).
The at least one amphiphilic lipid chosen from nonionic amphiphilic lipids and anionic amphiphilic lipids may be present in the aqueous phase (if more hydrophilic in nature) or in the oily phase (if more lipophilic in nature) of the nanoemulsion.
The at least one amphiphilic lipid chosen from nonionic amphiphilic lipids and anionic amphiphilic lipids may be present in the nanoemulsion of the invention in an amount ranging, for example, from 0.2% to 15% by weight relative to the total weight of the nanoemulsion, such as from 1% to 8% by weight relative to the total weight of the nanoemulsion.
The weight ratio of the amount of oily phase with respect to the amount of the at least one amphiphilic lipid (surfactant) ranges for example from 1:1 to 10:1, such as from 1.2:1 to 10:1, further such as from 1.5:1 to 6:1, and furthermore such as from 2:1 to 5:1. The expression xe2x80x9camount of oily phasexe2x80x9d herein means the total amount of constituents of this phase excluding the amount of the at least one amphiphilic lipid chosen from nonionic amphiphilic lipids and anionic amphiphilic lipids.
In one embodiment of the invention, the nanoemulsion of the invention may also comprise at least one additional ionic amphiphilic lipid other than the ionic amphiphilic lipids described above. Such additional ionic amphiphilic lipids may be added to possibly further improve the stability of the dispersion.
The at least one additional ionic amphiphilic lipid which may be used in the nanoemulsions of the invention can, for example, be chosen from cationic amphiphilic lipids and anionic amphiphilic lipids other than the anionic amphiphilic lipids described above, such as from:
alkaline salts of dicetyl phosphate and of dimyristyl phosphate;
alkaline salts of cholesteryl sulfate;
alkaline salts of cholesteryl phosphate;
lipoamino acids and salts thereof, such as monosodium and disodium acylglutamates, for instance the disodium salt of N-stearoyl-L-glutamic acid, sold under the name ACYLGLUTAMATE HS21 by Ajinomoto;
sodium salts of phosphatidic acid;
phospholipids; and
alkylsulfonic derivatives of formula: 
xe2x80x83in which R, which may be identical or different in embodiments wherein more than one of said alkylsulfonic derivative is used, is chosen from C16-C22 alkyl groups, such as C16H33 and C18H37 groups, and M is chosen from alkali metals and alkaline-earth metals, such as sodium.
Representative cationic amphiphilic lipids that can be used in the nanoemulsions of the invention can be chosen from, for example, quaternary ammonium salts, fatty amines, and salts thereof.
The quaternary ammonium salts are, for example, chosen from:
A) quaternary ammonium salts of formula (IV) below: 
in which:
R1, R2, R3, and R4, which may be identical or different, are each chosen from linear and branched aliphatic groups comprising from 1 to 30 carbon atoms, and aromatic groups, such as aryl and alkylaryl groups. The aliphatic groups can comprise hetero atoms, such as oxygen, nitrogen, and sulfur, and halogens. And the aliphatic groups can be chosen, for example, from alkyl, alkoxy, polyoxy(C2-C6)alkylene, alkylamide, (C12-C22)alkylamido(C2-C6)alkyl, (C12-C22)alkylacetate, and hydroxyalkyl groups comprising from 1 to 30 carbon atoms;
Xxe2x88x92 is an anion chosen from halides, phosphates, acetates, lactates, (C2-C6)alkyl sulfates, alkyl sulfonates, and alkylaryl sulfonates;
B) quaternary ammonium salts of imidazolinium, such as, for example, the salts of formula (V) below: 
in which:
R5 is chosen from alkenyl and alkyl groups comprising from 8 to 30 carbon atoms, for example groups derived from tallow fatty acid,
R6 is chosen from a hydrogen atom, C1-C4 alkyl groups, and alkenyl and alkyl groups comprising from 8 to 30 carbon atoms,
R7 is chosen from C1-C4 alkyl groups,
R8 is chosen from a hydrogen atom and C1-C4 alkyl groups,
Xxe2x88x92 is an anion chosen from halides, phosphates, acetates, lactates, alkyl sulfates, alkyl sulfonates, and alkylaryl sulfonates.
In one embodiment, for example, R5 and R6 arm chosen from alkenyl and alkyl groups comprising from 12 to 21 carbon atoms, for example, alkenyl and alkyl groups derived from tallow fatty acid, and wherein said R5 and R6 are chosen such that said quaternary ammonium salts of imidazolinium comprise at least one alkenyl group and at least one alkyl group, R7 is methyl, and R8 is hydrogen. Such products are, for example, (1) Quaternium-27 (International Cosmetic Ingredient Dictionary and Handbook, hereafter xe2x80x9cCTFAxe2x80x9d, 1997), i.e., xe2x80x9cRewoquatxe2x80x9d W75, W75PG, and W90, and (2) Quaternium-83 (CTFA 1997), i.e., xe2x80x9cRewoquatxe2x80x9d W75HPG, which are sold by the company Witco.
Additionally, the quaternary ammonium salts are, for example, chosen from:
C) diquaternary ammonium salts of formula (VI): 
in which:
R9 is chosen from aliphatic groups comprising from 16 to 30 carbon atoms,
R10, R11, R12, R13 and R14, which may be identical or different, are each chosen from a hydrogen atom and alkyl groups comprising from 1 to 4 carbon atoms, and
Xxe2x88x92 is an anion chosen from halides, acetates, phosphates, nitrates and methyl sulfates.
For example, such diquaternary ammonium salts can comprise propane tallow diammonium dichloride.
D) Quaternary ammonium salts comprising at least one ester function. The quaternary ammonium salts comprising at least one ester function that can be used according to the invention are, for example, those of formula (VII) below: 
in which:
R15 is chosen from C1-C6 alkyl groups, C1-C6 hydroxyalkyl groups and C1-C6 dihydroxyalkyl groups;
R16 is chosen from:
acyl groups of the following formula: 
wherein R19 is defined below,
linear and branched, saturated and unsaturated, C1-C22 hydrocarbon-based groups, and
a hydrogen atom;
R18 is chosen from:
acyl groups of the following formula: 
wherein R21 is defined below,
linear and branched, saturated and unsaturated, C1-C6 hydrocarbon-based groups, and
a hydrogen atom;
R17, R19 and R21, which may be identical or different, are each chosen from linear and branched, saturated and unsaturated, C7-C21, hydrocarbon-based groups;
n, p and r, which may be identical or different, are each chosen from integers ranging from 2 to 6;
y is chosen from integers ranging from 1 to 10;
x and z, which may be identical or different, are each chosen from integers ranging from 0 to 10;
Xxe2x88x92 is chosen from simple and complex, organic and inorganic anions;
provided that the sum x+y+z is from 1 to 15, and that when x is 0, then R16 is chosen from linear and branched, saturated and unsaturated, C1-C22 hydrocarbon-based groups, and that when z is 0, then R18 is (chosen from linear and branched, saturated and unsaturated, C1-C6 hydrocarbon-based groups.
In one embodiment, the R15 alkyl groups may be linear or branched and further, for example, linear.
For example, R15 may be chosen from methyl, ethyl, hydroxyethyl and dihydroxypropyl groups and further for example from methyl and ethyl groups.
The sum x+y+z may for example range from 1 to 10.
When R16 is chosen from linear and branched, saturated and unsaturated, C1-C22 hydrocarbon-based groups, R16 may be long and comprise from 12 to 22 carbon atoms, or short and comprise from 1 to 3 carbon atoms.
When R18 is chosen from linear and branched, saturated and unsaturated, C1-C6 hydrocarbon-based groups, R18 may for example comprise from 1 to 3 carbon atoms.
R17, R19 and R21, which may be identical or different, can each, for example, be chosen from linear and branched, saturated and unsaturated C11-C21 hydrocarbon-based groups, and for example from linear and branched, saturated and unsaturated, C11-C21, alkyl and alkenyl groups.
x and z, which may be identical or different, can for example each be chosen from 0 or 1.
y for example may be equal to 1.
n, p and r, which may be identical or different, can for example each be chosen from 2 and 3 and in one embodiment equal to 2.
The anion for example can be chosen from halides (chloride, bromide, and iodide) and alkyl sulfates, such as methyl sulfate. However, methanesulfonate, phosphate, nitrate, tosylate, anions derived from organic acids, such as acetate and lactate, and any other anions compatible with the ammonium comprising an ester function, may be used.
As a further example, the anion Xxe2x88x92 can be chosen from chloride and methyl sulfate.
Further examples of ammonium salts of formula (VII) are those in which:
R15 is chosen from methyl and ethyl groups,
x and y are equal to 1;
z is equal to 0 or 1;
n, p and r are equal to 2;
R16 is chosen from:
acyl groups: 
xe2x80x83wherein R19 is defined below,
methyl, ethyl and C14-C22 hydrocarbon-based groups, and
a hydrogen atom;
R18 is chosen from:
acyl groups: 
wherein R2, is defined below,
a hydrogen atom;
R17, R19 and R21, which may be identical or different, are each chosen from linear and to branched, saturated and unsaturated, C13-C17 hydrocarbon-based groups, such as from linear and branched, saturated and unsaturated C13-C17 alkyl and alkenyl groups.
The hydrocarbon-based groups can for example be linear.
Representative compounds of formula (VII) are chosen from diacyloxyethyldimethylammonium, diacyloxyethylhydroxyethylmethylammonium, monoacyloxyethyldihydroxyethylmethylammonium, triacyloxyethylmethylammonium and monoacyloxyethylhydroxyethyldimethylammonium salts (for example chloride and methyl sulfate). The acyl groups can for example comprise from 14 to 18 carbon atoms and can for example be obtained from plant oils, such as palm oil and sunflower oil. When the compound comprises several acyl groups, these groups, which may be independently chosen, may independently be identical or different.
These products are obtained, for example, by direct esterification of compounds chosen from triethanolamine, triisopropanolamine, alkyidiethanolamines and alkyldiisopropanolamines, which are optionally oxyalkylenated, with fatty acids or with fatty acid mixtures of plant or animal origin, and by transesterification of the methyl esters thereof. This esterification is followed by a quaternization using an alkylating agent such as alkyl halides (such as methyl and ethyl halides), dialkyl sulfates (for example dimethyl and diethyl sulfates), methyl methanesulfonate, methyl para-toluenesulfonate, glycol chlorohydrin and glycerol chlorohydrin.
Such compounds are sold, for example, under the names Dehyquart by the company Henkel, Stepanquat by the company Stepan, Noxamium by the company Ceca and Rewoquat WE 18 by the company Rewo-Witco.
One embodiment of the invention can comprise at least one quaternary ammonium monoester salt, at least one quaternary ammonium diester salt, and at least one quaternary ammonium triester salt, wherein said quaternary ammonium diester salt is present in a majority by weight.
Such an embodiment may comprise, for example, 15% to 30% by weight of acyloxyethyldihydroxyethylmethylammonium methyl sulfate, 45% to 60% by weight of diacyloxyethylhydroxyethylmethylammonium methyl sulfate, and 15% to 30% by weight of triacyloxyethylmethylammonium methyl sulfate, wherein said acyl groups comprise from 14 to 18 carbon atoms, and wherein said acyl groups are derived from palm oil that is optionally partially hydrogenated.
It is also possible to use the ammonium salts comprising at least one ester function, described in U.S. Pat. Nos. 4,874,554 and 4,137,180, the disclosures of which are incorporated by reference herein.
Representative quaternary ammonium salts of formula (IV) include tetraalkylammonium chlorides such as, for example, dialkyldimethylammonium chlorides and alkyltrimethylammonium chlorides, in which the alkyl group comprises from 12 to 22 carbon atoms, for example behenyltrimethylammonium chloride, distearyidimethylammonium chloride, cetyltrimethylammonium chloride., and benzyldimethylstearylammonium chloride, and, stearamidopropyidimethyl(myristyl acetate)ammonium chloride sold under the name xe2x80x9cCepharyl 70xe2x80x9d by the company Van Dyk.
According to one embodiment of the invention, the quaternary ammonium salt can be behenyltrimethylammonium chloride.
The at least one additional ionic amphiphilic lipid chosen from cationic amphiphilic lipids and anionic amphiphilic lipids is generally present in the nanoemulsion of the invention in an amount ranging for example from 0.01% to 10% by weight relative to the total weight of the nanoemulsion, such as for example from 0.2% to 5% by weight relative to the total weight of the nanoemulsion.
The at least one oil that may be used in the nanoemulsion of the invention is, for example, chosen from:
animal and plant oils formed by fatty acid esters of polyols, such as liquid triglycerides, for example sunflower oil, corn oil, soybean oil, avocado oil, jojoba oil, marrow oil, grape-seed oil, sesame oil, hazelnut oil, fish oils, glyceryl tricaprocaprylate, and plant and animal oils of formula R9COOR10 in which R9 is chosen from fatty acid residues comprising from 7 to 29 carbon atoms and R10 is chosen from linear and branched hydrocarbon-based chains comprising from 3 to 30 carbon atoms, such as alkyl and alkenyl, for example, purcellin oil and liquid jojoba wax;
natural and synthetic essential oils such as, for example, eucalyptus oil, lavandin oil, lavender oil, vetiver oil, Litsea cubeba oil, lemon oil, sandalwood oil, rosemary oil, camomile oil, savory oil, nutmeg oil, cinnamon oil, hyssop oil, caraway oil, orange oil, geraniol oil, cade oil and bergamot oil;
synthetic oils;
mineral oils such as hexadecane and liquid paraffin;
halogenated oils, such as fluorocarbons, for example, fluoroamines (including for example perfluorotributylamine), fluorohydrocarbons (including for example perfluorodecahydronaphthalene), fluoroesters and fluoroethers;
esters of at least one mineral acid and of at least one alcohol;
liquid carboxylic acid esters; and
volatile and non-volatile silicone oils.
Volatile and non-volatile silicone oils can for example be used in the presence of at least one non-silicon oil (oil which does not contain silicium atom). When used, the total amount of such silicone oils is generally an amount ranging for example from 5% to 50% by weight relative to the total weight of oils.
The synthetic oils can be chosen from for example polyolefins, such as poly-xcex1-olefins and further such as:
poly-xcex1-olefins chosen from hydrogenated and non-hydrogenated polybutene poly-xcex1-olefins, such as hydrogenated and non-hydrogenated polyisobutene poly-xcex1-olefins.
One embodiment may comprise at least one isobutylene oligomer with a molecular weight of less than 1 000 and at least one polyisobutylene with a molecular weight of greater than 1 000 such as for example ranging from 1 000 to 15 000.
Representative carboxylic acid esters include monocarboxylic acid esters, dicarboxylic acid esters, tricarboxylic acid esters, and tetracarboxylic acid esters. The total number of carbons in the esters is generally equal to 10 or more, such as less than 100 and further such as less than 80.
The monocarboxylic acid esters can be chosen from saturated and unsaturated, linear and branched C1-C26 aliphatic acid monoesters derived from alcohols chosen from saturated and unsaturated, linear and branched C1-C26 aliphatic alcohols, wherein the total number of carbons in the esters is generally equal to 10 or more.
It is also possible to use esters derived from C4-C22 dicarboxylic acids and C1-C22 alcohols, esters derived from C4-C22 tricarboxylic acids and C1-C22 alcohols, esters derived from acids chosen from mono-, di-, and tricarboxylic acids and alcohols chosen from C2-C26 di-, tri-, tetra- and pentahydroxy alcohols.
Representative esters mentioned above which can be used include ethyl palmitate, isopropyl palmitate, 2-ethylhexyl palmitate, 2-octyldecyl palmitate, alkyl myristates such as isopropyl myristate, butyl myristate, cetyl myristate and 2-octyldodecyl myristate, hexyl stearate, butyl stearate, isobutyl stearate; dioctyl malite, hexyl laurate, 2-hexyldecyl laurate, isononyl isononanate, and cetyl octanoate.
The at least one oil of the nanoemulsions in accordance with the invention is generally present in an amount ranging for example from 2% to 40% by weight relative to the total weight of the nanoemulsion, such as for example from 4% to 30% by weight relative to the total weight of the nanoemulsion, and further such as for example from 8% to 20% by weight relative to the total weight of the nanoemulsion.
According to one embodiment, such as for example an embodiment of the invention that is used for hair compositions, the compositions according to the invention can also comprise at least one aminosilicone.
Hereinabove and hereinbelow, the terms at least one xe2x80x9csiliconexe2x80x9d and xe2x80x9cpolysiloxanexe2x80x9d are synonymous and are understood to include linear and cyclic, branched and crosslinked organosilicon polymers and organosilicon oligomers of variable molecular weight, obtained by polymerization and/or polycondensation of suitably functionalized silanes, and which comprise repeating units in which the silicon atoms are connected together by oxygen atoms (siloxane bond xe2x89xa1Sixe2x80x94Oxe2x80x94Sixe2x89xa1) and are optionally substituted with at least one hydrocarbon-based group, which is bonded by way of a carbon atom of said hydrocarbon-based group to said silicon atoms. The most common hydrocarbon-based groups are alkyl groups, such as C1-C10 alkyl groups and further such as methyl, fluoroalkyl groups, aryl groups, such as phenyl, and alkenyl groups such as Vinyl; other groups that can be bonded, either directly or by way of a hydrocarbon-based linking group, to the siloxane chain can be chosen from a hydrogen atom, halogen""s, such as chlorine, bromine and fluorine, thiols, alkoxy groups, polyoxyalkylene groups, such as polyoxyethylene and polyoxypropylene, polyether groups, hydroxyl, hydroxyalkyl groups, amide groups, acyloxy groups, acyloxyalkyl groups, amphoteric groups, betaine groups, anionic groups such as carboxylates, thioglycolates, sulfosuccinates, thiosulfales, phosphates and sulfates, this list obviously being in no way limiting (so-called xe2x80x9corganomodifiedxe2x80x9d silicones).
According to the invention, the term at least one xe2x80x9caminosiliconexe2x80x9d means any silicone comprising at least one amine chosen from primary, secondary, and tertiary amines or at least one quaternary ammonium group. Mention may thus be made of:
(a) polysiloxanes referred to in the CTFA dictionary as xe2x80x9camodimethiconexe2x80x9d of formula (IV): 
xe2x80x83in which xxe2x80x2 and yxe2x80x2 are integers chosen such that generally the weight-average molecular weight of said aminosilicone ranges from 5 000 to 500 000 approximately;
(b) said at least one aminosilicone corresponding to formula (V):
Rxe2x80x2aG3xe2x88x92axe2x80x94Si(OSiG2)nxe2x80x94(OSiGbRxe2x80x22xe2x88x92b)mxe2x80x94Oxe2x80x94SiG3xe2x88x92axe2x80x94Rxe2x80x2axe2x80x83xe2x80x83(V)
xe2x80x83in which:
G is chosen from a hydrogen atom, a phenyl group, OH group, and C1-C8 alkyl groups, for example methyl,
a is an integer ranging from 0 to 3, and in one embodiment a is 0,
b is chosen from 0 and 1, and in one embodiment b is 1,
m and n are numbers such that the sum (n+m) can range for example from 1 to 2 000, such as for example from 50 to 150, wherein n can be for example chosen from numbers ranging from 0 to 1 999, such as for example from 49 to 149, and wherein m can be chosen from numbers ranging for example from 1 to 2 000, such as for example from 1 to 10;
Rxe2x80x2 is a monovalent group of formula xe2x80x94CqH2qL in which q is a number from 2 to 8 and L is an optionally quaternized amine group chosen from the groups:
xe2x80x94NRxe2x80x3xe2x80x94CH2xe2x80x94CH2xe2x80x94Nxe2x80x2(R1)2,
xe2x80x94N(Rxe2x80x3)2,
xe2x80x94N+(Rxe2x80x3)3Axe2x88x92,
xe2x80x94N+H(Rxe2x80x3)2Axe2x88x92,
xe2x80x94N+H2(Rxe2x80x3)Axe2x88x92, and
xe2x80x94N(Rxe2x80x3)xe2x80x94CH2xe2x80x94CH2xe2x80x94N+Rxe2x80x3H2Axe2x88x92,
in which Rxe2x80x3 can be chosen from a hydrogen atom, phenyl groups, benzyl groups, and saturated monovalent hydrocarbon-based groups, such as for example an alkyl group comprising from 1 to 20 carbon atoms, and Axe2x88x92 is chosen from halide ions such as, for example, fluoride, chloride, bromide and iodide.
One aminosilicone of said at least one aminosilicone corresponding to formula (V) is known as xe2x80x9ctrimethylsilylamodimethiconexe2x80x9d of formula (VI): 
in which:
m and n are numbers such that the sum (n+m) can range for example from 1 to 2 000, such as for example from 50 to 150, wherein n can be for example chosen from numbers ranging from 0 to 1 999, such as for example from 49 to 149, and wherein m can be chosen from numbers ranging for example from 1 to 2 000, such as for example from 1 to 10.
Such polymers are described, for example in patent application EP-A-95238, the disclosure of which is incorporated herein by reference.
Additional said at least one aminosilicone of the invention include:
(c) said at least one aminosilicone of formula (VII): 
xe2x80x83in which:
R5 is chosen from monovalent hydrocarbon-based groups comprising from 1 to 18 carbon atoms, such as C1-C18 alkyl groups and C2-C18 alkenyl groups, for example methyl;
R6 is chosen from divalent hydrocarbon-based groups, such as divalent C1-C18 alkylene groups and divalent C1-C18 alkylenoxy groups, for example C1-C8 alkylenoxy groups, wherein said R6 is bonded to the Si by way of an SiC bond;
Qxe2x88x92 is an anion that can be for example chosen from halide ions, such as chloride, and organic acid salts (such as acetate);
r is an average statistical value ranging from 2 to 20, such as from 2 to 8;
s is an average statistical value ranging from 20 to 200, such as from 20 to 50.
Such aminosilicones are described more particularly in U.S. Pat. No. 4,185,087, the disclosure of which is incorporated by reference herein.
A silicone which falls within this class is the silicone sold by the company Union Carbide under the name xe2x80x9cUcar Silicone ALE 56xe2x80x9d.
Further examples of said at least one aminosilicone include:
d) quaternary ammonium silicones of formula (VIIb): 
xe2x80x83in which:
groups R7, which may be identical or different, are each chosen from monovalent hydrocarbon-based groups comprising from 1 to 18 carbon atoms, such as C1-C18 alkyl groups, for example methyl, C2-C18 alkenyl groups, and rings comprising 5 or 6 carbon atoms;
R6 is chosen from divalent hydrocarbon-based groups, such as divalent C1-C18 alkylene groups and divalent C1-C18alkylenoxy, for example C1-C8, group connected to the Si by an SiC bond;
R8, which may be identical or different, represent a hydrogen atom, a monovalent hydrocarbon-based group comprising from 1 to 18 carbon atoms, and in particular a C1-C18 alkyl group, a C2-C18 alkenyl group or a group xe2x80x94R6xe2x80x94NHCOR7;
Xxe2x88x92 is an anion such as a halide ion, in particular chloride, or an organic acid salt (acetate, etc.);
r represents an average statistical value from 2 to 200 and in particular from 5 to 100.
Such silicones are described, for example, in application EP-A-0 530 974, the disclosure of which is incorporated by reference herein.
Silicones falling within this class are the silicones sold by the company Goldschmidt under the names Abil Quat 3270, Abil Quat 3272 and Abil Quat 3474.
According to the invention, said at least one aminosilicone can be present in at least one form chosen from the form of an oil, the form of a solution chosen from aqueous, alcoholic and aqueous-alcoholic solutions, the form of a dispersion, and the form of an emulsion.
In one embodiment, the aminosilicones can be present in the form of an emulsion, such as emulsions chosen from microemulsions and nanoemulsions.
The product sold under the name xe2x80x9cCationic Emulsion DC 929xe2x80x9d by Dow Corning, which comprises, besides amodimethicone, a cationic surfactant derived from tallow fatty acids, referred to as Tallotrimonium (CTFA), in combination with a nonionic surfactant, known under the name xe2x80x9cNonoxynol 10xe2x80x9d, can be used for example.
The product sold under the name xe2x80x9cCationic Emulsion DC 939xe2x80x9d by Dow Corning, which comprises, besides amodimethicone, a cationic surfactant, trimethylcetylammonium chloride, in combination with a nonionic surfactant, trideceth-12, can also be used for example.
Another commercial product which can be used according to the invention is the product sold under the name xe2x80x9cDow Corning Q2 7224xe2x80x9d by Dow Corning, comprising, in combination, the trimethylsilylamodimethicone of formula (IV), a nonionic surfactant of formula: C8H17xe2x80x94C6H4xe2x80x94(OCH2CH2)nxe2x80x94OH in which n=40, also known as octoxynol-40, another nonionic surfactant of formula: C12H25xe2x80x94(OCH2xe2x80x94CH2)nxe2x80x94OH in which n=6, also known as isolaureth-6, and glycol.
The at least one aminosilicone is generally present in an amount ranging for example from 0.05% to 10% by weight relative to the total weight of the nanoemulsion, such as for example from 0.1% to 5% by weight relative to the total weight of the nanoemulsion, and further such as from 0.3% to 3% by weight relative to the total weight of the nanoemulsion.
The nanoemulsions in accordance with the present invention may comprise at least one solvent, for example, if desired, to improve the transparency of the formulation.
The at least one solvent can be for example chosen from:
C1-C8 alcohols such as ethanol;
glycols such as glycerol, propylene glycol, 1,3-butylene glycol, dipropylene glycol, polyethylene glycols comprising from 4 to 16, for example, from 8 to 12 ethylene oxide units.
The at least one solvent such as those mentioned above are generally present in the nanoemulsions of the invention in an amount ranging for example from 0.01% to 30% by weight relative to the total weight of the nanoemulsion.
In addition, the use of the alcohols as defined above, in an amount of at least 5% by weight relative to the total weight of the nanoemulsion, such as for example at least 15% by weight relative to the total weight of the nanoemulsion, may make it possible for one skilled in the art to obtain nanoemulsions without a preserving agent.
The nanoemulsions of the invention can additionally comprise at least one active agent chosen from water-soluble, water-dispersible, and liposoluble cosmetic active agents and water-soluble, water-dispersible, and liposoluble dermopharmaceutical active agents. The liposoluble active agents are present in the oily globules of the nanoemulsion, while the water-soluble and water-dispersible active agents are present in the aqueous phase of the nanoemulsion. Non-limiting examples of said at least one active agent include vitamins and derivatives thereof, such as vitamin E, vitamin E acetate, vitamin C and its esters, B vitamins, vitamin A alcohol and vitamin A retinol, vitamin A acid and vitamin A retinoic acid and its derivatives, provitamins such as panthenol, vitamin A palmitate, niacinamide, ergocalciferol, antioxidants, essential oils, wetting agents, silicone and non-silicone sunscreens, preserving agents, sequestering agents, softeners, dyes, viscosity modifiers, foam modifiers, foam stabilizers, nacreous agents, pigments, moisturizers, antidandruff agents, antiseborrhoeic agents, proteins, ceramides, pseudoceramides, fatty acids comprising linear and branched C16-C40 chains, such as 18-methyl eicosanoic acid, plasticizers, hydroxy acids, electrolytes, polymers, such as cationic polymers, and fragrances.
The oil globules in the nanoemulsions of the invention can for example have an average size ranging from 20 nm to 150 nm, such as for example from 30 nm to 100 nm and further such as for example from 40 nm to 80 nm.
The nanoemulsions according to the invention generally have a transparent to blueish appearance. Their transparency is measured by a coefficient of transmittance at 600 nm ranging for example from 10% to 90%, or alternatively by a turbidity ranging for example from 60 NTU to 600 NTU such as for example from 70 NTU to 400 NTU, the turbidity being measured using a Hach Model 2100 P portable turbidimeter.
The nanoemulsions of the invention may be obtained by a process comprising:
(1) combining the aqueous phase and the oily phase by mixing with vigorous stirring at a temperature of less than 45xc2x0 C.,
(2) homogenizing said combination at a pressure of greater than 5xc3x97107 Pa such as ranging for example from 6xc3x97107 to 18xc3x97107 Pa.
Such a process makes it possible to produce, at room temperature, nanoemulsions that tend to be compatible with heat-sensitive active compounds and that can comprise large amounts of oils, such as fragrances comprising fatty substances, whereby the possibility of denaturing such oils tends to be reduced.
Another subject of the invention is a composition for topical use such as a composition chosen from cosmetic compositions and dermopharmaceutical compositions, wherein said composition for topical use comprises a nanoemulsion comprising oil globules with an average size of less than 150 nm comprising at least one oil, at least one amphiphilc lipid, and at least one nonionic polymer comprising at least one hydrophobic block and at least one hydrophilic block.
The compositions in accordance with the invention may be used for at least one use chosen from washing keratin materials, cleaning keratin materials, and removing make-up from keratin materials such as the hair, the skin, the eyelashes, the eyebrows, the nails and mucous membranes.
The compositions of the invention can for example be in forms chosen from shampoos, rinse-out conditioners, leave-in conditioners, permanent-waving compositions, relaxing compositions, dyeing compositions, bleaching compositions, compositions to be applied before a procedure chosen from dyeing, bleaching, permanent-waving and relaxing the hair, compositions to be applied after a procedure chosen from dyeing, bleaching, permanent-waving and relaxing the hair, and compositions to be applied between the two steps of a procedure chosen from permanent-waving and relaxing the hair.
The compositions may also be in at least one form chosen from hairsetting lotions, blow-drying lotions, fixing compositions (lacquers), and styling compositions such as, for example, gels and mousses.
The compositions can be packaged in various forms chosen from vaporizers, pump-dispenser bottles and aerosol containers in order to ensure application of the composition in vaporized form or in the form of a mousse. Such packaging forms are indicated, for example, when it is desired to obtain a spray, a lacquer or a mousse for fixing or treating the hair.
When the composition according to the invention is packaged in aerosol form in order to obtain an aerosol lacquer or mousse, it comprises at least one propellant which may be chosen from volatile hydrocarbons such as n-butane, propane, isobutane and pentane, chlorohydrocarbons, fluorohydrocarbons, carbon dioxide, nitrous oxide, dimethyl ether, nitrogen and compressed air.
The compositions in accordance with the invention may be used to care for a keratin material chosen from for example hair, body skin, facial skin, eyelashes, eyebrows, nails, and mucous membranes.
The compositions in accordance with the invention may be used to make up keratin materials chosen from for example hair, body skin, facial skin, eyelashes, eyebrows, nails, and mucous membranes.
Another subject of the invention is a cosmetic product base, such as for example lotions, sera, milks, creams and eaux de toilette for caring, making-up, or removing make-up from keratin materials, such as for example body skin, facial skin, the scalp, the hair, the nails, the eyelashes, the eyebrows, and mucous membranes, and further such as for example the lips, wherein said cosmetic product base comprises at least one nanoemulsion comprising oil globules with an average, size of less than 150 nm comprising at least one oil, at least one amphiphilc lipid, and at least one nonionic polymer comprising at least one hydrophobic block and at least one hydrophilic block.
Another subject of the invention relates to a non-therapeutic care process for keratin material comprising applying a nanoemulsion comprising oil globules with an average size of less than 150 nm comprising at least one oil, at least one amphiphilc lipid, and at least one nonionic polymer comprising at least one hydrophobic block and at least one hydrophilic block to said keratin material chosen from for example the skin, the hair, the eyelashes, the eyebrows, the nails, mucous membranes and the scalp.
Concrete examples illustrating the invention are indicated below without however exhibiting a limiting character.
Other than in the operating examples, or where otherwise indicated, all numbers expressing quantities of ingredients, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term xe2x80x9cabout.xe2x80x9d Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.
Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.